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U.S. Department of Energy
Office of Scientific and Technical Information

Steam turbine rotor reliability: task details. [STRAP]

Technical Report ·
DOI:https://doi.org/10.2172/6530148· OSTI ID:6530148

The overall project objective is to establish and confirm by test the viability of a steam turbine rotor component lifetime prediction system that is based on finite element thermo-elastic stress analysis and fracture mechanics, and that uses details of field NDE inspection results as input to the calculations. The effort to date has been composed of four tasks contracts. These tasks are: lifetime prediction analysis system, nondestructive evaluation, destructive tests, and material mechanical properties measurements. The automated Steam Turbine Rotor Analysis Program (STRAP) was developed to facilitate the prediction of rotor lifetime given the duty cycle of the turbine and the results of ultrasonic examination from the rotor bore. STRAP consists in part of a preprocessor code that generates the boundary conditions and finite element mesh for transient and steady-state temperature and stress analysis employing the ANSYS general-purpose structural analysis code. A postprocessor contains fracture toughness, stress-rupture, yield strength, and fatigue crack growth rate data for air-melted 1 Cr--Mo--V forgings, on the basis of which the local stress and temperature values are screened to determine the critical crack size, the initial crack size that could grow to critical size within a specified number of hours or cycles, and the minimum area fraction of defects that could link up to result in a significant crack. A boresonic data reduction code allows rapid sorting of indicated flaw sizes and locations to determine the regions of greatest defect density. The four separate task reports that detail the project research since January 1976 are presented. Each report is self-contained, with its own summary, contents, and references, Also available is a project summary report, which presents highlights of the research results.

Research Organization:
Battelle Columbus Labs., OH (USA); Southwest Research Inst., San Antonio, TX (USA); Westinghouse Electric Corp., Pittsburgh, PA (USA). Research and Development Center; Westinghouse Electric Corp., Philadelphia, PA (USA)
OSTI ID:
6530148
Report Number(s):
EPRI-NP-923
Country of Publication:
United States
Language:
English